Synthesis and application of magnetic bio-sorbent for determination trace amounts of thymol

Abstract

A reliable and sensitive method was developed for the determination of thymol by magnetic dispersive micro-solid phase extraction (MD-µSPE) based on the use of Escherichia coli bacteria. It was immobilized on the γ-Fe2O3 magnetic nanoparticles and used as a bio-sorbent for MD-µSPE. The properties of the synthesized bio-sorbent were characterized by Fourier transform infrared (FT-IR) spectroscopy, energy dispersive X-ray (EDX), and field emission scanning electron microscopy (FE-SEM). Central composite design (CCD) combined with desirability function approach was applied to search for optimal operational conditions. Under the optimum conditions specified as: 25 min ultrasonic time, pH=5, 30 mg of bio-adsorbent, and temperature 35 °C, high and reasonable linear range over 30 - 500 ng mL-1 (R2 > 0.9965) with limit of detection (LOD) 9.183 ng mL−1 were obtained. Finally, the proposed method was successfully used for extraction and determination of thymol in food and cosmetic samples.